Friction wrench



Sept. 22, 1959 i J. A. PETERSON ETAL 3 FRICTION WRENCH Filed March 18,1957 Can/.5 OLseu ATTOR EY United rates atent FRICTION WRENCH JosephArvid Peterson and Carl E. Olsen, Houston, Tex. Application March 18,1957, Serial No. 646,840.

4 Claims. (Cl. 81-.-67)

The invention relates togripping devices or wrenches and more.particularly. to gripping. devices of. the type adaptedto. tightly andfrictionally embrace cylindrical objects such as pipes or bars.

In thepast, gripping devices, of the above type, have normally beenequipped with somewhat complicated and inconveniently operatedstructures for locking or retainingthe. device in its work holdingposition. Some attempts have been made to. develop more convenientlyoperable locking means for gripping devices,.however, such previousattempts have resulted in unduly expensive and/or extremely. complicatedstructures.

Accordingly, it is a principal objectof the invention to 'provide anovel gripping device particularly adapted to be. readily engaged to .acylindrical object for applyingor resisting torques on the object.

Afurther object isto provide an inexpensive gripping device adapted to.be. conveniently handled and operated.

Another. object. resides in the. provision of a gripping device,characterized by a novel friction locking arrangement whose lockingaction is enhanced upon the application of torque to .thecmbracedobject.

Further objects and advantages of the invention will'be in part obviousand in part pointed out hereinafter.

The novel features of the inventionmay be best made clearwfrom thefollowing description and accompanying drawings in which:

Fignrel is a fragmentary side elevational view of a gripping device ofthe invention;

Figure. 2 is a fragmentary top plan view of the device;

Figure 3 is a bottom plan view of the device;

Figure 4 is a view of a jaw of the device taken in the direction of theadjacent arrow;

Figure 5 is a view of the device taken in the direction of the adjacentarrow; and

Figure 6 is a perspective view, partially in section, showing thedetails of a locking bolt illustrated in Figure l.

Referring to thedrawings, a gripping device of the invention preferablyincludes a main handle 10 and a girth 12 pivoted to the main handle. ThegirtltlZis adapted to embrace a cylindricalwvork object 14 andpreferably comprises a plurality of pivotall y intercon nected jaws 16,18, 2d pivoted to an outer free end of the main handle for bodilyswinging movement with respect thereto. Each of the jaws 16, 18, Zdandthe main handle lil maybe constructed of any suitable metal such asaluminum, and these parts may he formed by anydesirable process, suchasforging or casting.

The first jaw 16 (Figure 4) may be composed of two longitudinal,generally symmetrical sections 22, 24 connected togetheras by transverserivet 26 and/ or welding along the seam 28 therebetween. The top of thejaw preferably is provided with transversely spaced apeltured cars 30;The joined sections 22, 24 form lug 32 projecting laterally outwardlyfrom jaw 16 and having a verticallyf disposed blind hole 34 therein.This jaw 16 is pivotally connected to the forward--01? left end of mainice 2 handle '10 as viewed in Figure 1. For the tfiorwardpurpose, thisend of the handle 10 may be formed with a downwardly opening arcuateconcavity 36 therein for receiving a pin or bolt 38 extending throughthe apertured cars 30 of jaw 16. The handle 10 and. pin 38 may also bedrivingly and fixedly connected together as by means of an interlockingpin 40 suitably retained in alignedholes in the handle 10 and bolt 38.If desired, bolt 38 may be integral with the handle 16- constitutingtrunnions extending laterally from either side thereof for j ournallingin ears 30.

The lower end of the jaw 16 is suitably pivotally connected to theintermediate jaw 18, as by being bifurcated into apertured portions 42adapted to be fitted over a transversely bored end 44 of reduced widthon jaw/ 18 (Figure 5) and engaged thereto by a pivot pin 46 extendingthrough these portions 42 and the end 44. To limit the relative pivotalmovement between jaws 16, 18 inan opening direction, a lug 48 may beformed on the end 44 of. jaw 18 for engagement with a stop surface 50recessed in the jaw 16. Cooperating, transversely extending arcuatesurfaces "52, 54 are respectively formed in the jaws 16, 18 forreceiving the cylindrical work piece 14. j

The upper end of jaw 16 may also be bifurcated into apertured portions56 adapted to be fitted over a trans versely bored portion of jaw 26 andengaged thereto by pivot pin 58 extending through the aligned aperturesand bore.

The jaw 20 preferably includes a hand grip section 69 extendingrearwardly and integrally therefrom to constitute a secondary handle forthe gripping device, of smaller length than main handle 16? (as seen inFigure l). A transverse surface 62 is formed in jaw 26 for cooperationwith surfaces 52, 54 of jaws 16, 18 respectively to completely embracethe work piece 1d when the jaws are closed. The axial length-of thissurface 62 may be increased by forming arcuate, lateral extensions. 64on jaw 20. Relative pivotal movement between jaws 18, 21 in an openingdirection, may be limited by the provision of a stopsurface 66 on theunderside of jaw 26 adjacent pivot pin 58engageable with acomplementarily shaped surface 68 on the jaw 18.

The invention contemplates the provision of novel lockingmeans forretaining the jaws 16, 18, 20 in closed position, wherein they tightlyembrace the cylindrical work piece 14. An exemplary embodiment of suchmeans includes mutually engageable, friction locking surfaces on thebolt 38 and'free, inner end of jaw 20, and biasing means continuouslyurging the jaws 16, 18, 20 to pivotor swing bodily toward the mainhandle 10. These engageable, locking surfaces preferably are defined bya pair of side walls which diverge outwardly from adjacent the centralaxial region of bolt 38 to form a longitudinally extending recess ornotch 70 for receiving a transverse lip 72 projecting outwardly frominner end of jaw 20 andapproximately at a right angle to thelongitudinal axis of the jaw. The biasing means preferably includes acompression spring '74 arranged in the blind hole 34- in the lug 32' ofjaw 16for acting against an arcuate finger-like projectionorprotuberance 76 on the adjacentend'of main handle Ill. The outer endof this finger 76 is disposed in the upper end of the hole 34 and a pin78 is continuously pressed thereagainst by the spring.

In the operationof our novel gripping device, the jaws of the girth 12are readily moved to an open position by manual operation of handles 10,60 and the cylindrical work piece 14 is disposed therewithin. The jawsare thereafter moved to their closed position wherein the surfaces 52,54, 62 therein engage the surface of the work piece. The surfaces 52,54, 62 preferably are relatively smooth whereby they may tightly embracethe recess 70 of bolt 38, wherein the lip 72 will be engaged to theright hand inclined surface of this recess as 'viewed in Figure 1. Atthis time the jaws 16, 18, 20 will be desirably locked in closedposition, tightly embracing the work piece whereby the gripping devicemay be effectively utilized for applying or resisting torques or otherforces on the workpiece.

The action of the compression spring 7 3 will be seen to cause the mainhandle 10 and girth 12 to tend to swing or pivot toward each other. Thistendency of these parts to swing toward each other takes place about theaxis of bolt 38. The secondary handle 60 and jaw 20 will be preventedfrom swinging in a counter-clockwise direction about the axis of pivotpin 58 by reason of the presence of the work piece 14, acting as anabutting or stop surface for such swinging movement. Consequently, thetendency of these parts to swing together, produced by the action ofspring 74, will result in the development of a force in the region ofcontact between the lip 72 and recess 70, and acting on the lip 72 in adirection generally normal to the right hand surface of recess 70 anddownwardly to the left, as viewed in Figure 1. It will be evident thatsuch a force will produce a tight, positive friction lock on theworkpiece 14 by the jaws 16, 18, 20. In this connection, if the operatorholds only the main handle 10 at the outer end thereof, the weight ofthe jaws will result in a generally downwardly directed force pulling onthe jaws, tending to produce a clock-wise bodily swinging thereof aboutthe axis of bolt 38 away from handle 10. However, the compression spring74 is designed so that the magnitude of the forces produced thereby,tending to cause the pivoted jaws to swing bodily toward the main handlewill be suflicient to overcome the tendency of the jaws to swing awayfrom the main handle, whereby the force referred to above acting on thelip 72 of jaw 20 will still be developed for assuring the desired tightfriction lock of the jaws on the work piece. Furthermore, it should alsobe evident that movement of main handle 10 by the operator in acounterclockwise direction about the axis of the cylindrical work piece14 will initially eifect an inward movement of the projecting finger 76thereon further into the blind hole 34 whereby the compression of spring74 will be increased, thereby causing a corresponding increase in themagnitude of the force acting on the pivoted jaws to produce a bodilyswinging of these jaws toward the main handle while imparting acorresponding counter clockwise torque and movement to the work piece14. Clockwise swinging of main handle 10 to turn the work piece 14 in aclockwise direction will be noted to cause bolt 38 to be rotated ormoved therewith so that the surface of recess 70 engaging lip 72 will bedriven into tighter engagement with lip 72, thereby preserving andactually enhancing the gripping action of the jaws.

It will be understood, that the girth 12 is not adapted for all sizes ofcylindrical work objects, although some variation in diameter can beaccommodated by the pivoted jaw assembly inasmuch as the jaw 20 andsecondary handle 62 will be in locked position virtually as soon as thelip 72 on jaw 20 enters the recess 70, wherein the circircumferentialdistance defined by the cooperating surfaces 52, 54, 62 of the jaws willbe the greatest, and the jaws will also be locked for all positionsbetween this initial locked position and a final position of the jaw 20,wherein the secondary handle will be generally parallel to the mainhandle 10 and the lip 72 will be disposed at the innermost portion ofthe recess 70, this latter position involving the maximum closingmovement of jaw 20 toward jaws 16, 18 thereby presenting the smallestcircumferential distance defined by the cooperating surfaces 52, 54, 62.In the maximum closed position of jaw 20, the lip 72 thereof will bedisposed at the innermost portion of recess 70 whereby any force applieddownwardly at the outer endof main handle 10, due to the large lever ormoment arm of handle 10 and the small moment arm for the reaction forceon lip 72 (both moment arms being measured to the axis of bolt 38), willresult in a greatly amplified force acting on lip 72 to urge the jaw 20toward jaws 16, 18. It will also be appreciated that the tightening orgripping action can be increased by moving handle toward handle 10 sothat the gripping device will operate effectively even with small workpieces having slippery or smooth outer surfaces.

It will be apparent that in imparting torque to the work piece 14 theoperator may grasp both the main handle and the secondary handle. Thesecondary handle has been found to greatly facilitate the opening andclosing of the girth 12, and in this regard, it will only be necessaryto apply opposite outwardly directed forces to the main handle 10 andsecondary handle 60 to separate them for removal of the lip 72 from therecess 70 whereby the girth may be opened to release its grip on thework piece.

When the gripping device is utilized for resisting external forcesapplied to the work piece 14, it will be noted that any externalcounterclockwise torque applied to the work piece (as viewed in Figure1), that is, a counterclockwise torque not exerted on the work piece 14by the gripping device, will initially tend to produce a bodily swingingof the pivoted jaws toward the main handle which is held stationary bythe operator. This tendency of the jaw assembly to swing toward the mainhandle will increase the contact force between lip 72 and the engagedsurface of recess 70 whereby the jaws will be pressed more tightlyagainst the work piece to resist and prevent rotation thereof. If anexternal clockwise torque is applied to the work piece, the pivoted jawassembly will then initially tend to swing bodily away from the mainhandle 10. However, this tendency will be overcome by the additionalcompression of spring 74, occasioned by any bodily movement of the jawsaway from the handle 10, which will be effective to preventdisengagement of the lip 72 from recess 70, thereby keeping the jaws inclosed position.

It will thus be seen that the objects of this invention have been fullyand effectively accomplished. It will be realized, however, that theforegoing specific embodiment has been shown and described only for thepurpose of illustrating the principles of the invention and is subjectto extensive change without departure from such principles. Therefore,this invention includes all modifications encompassed within the spiritand scope of the appended claims.

We claim:

1. A gripping device comprising: a main handle having a forward endportion; a jaw assembly having a plurality of pivotally interconnectedjaws with cooperating surfaces for embracing an object when said jawsare pivoted toward each other into closed position; said jaw assemblyhaving one end thereof pivoted on a transverse axis to the 7 forward endportion of said main handle and an opposite free end movable toward saidmain handle; biasing means acting between the pivotally connected end ofsaid jaw assembly and the forward end portion of said handle forcontinuously urging said jaws toward said main handle; cooperable meansincluding a transverse locking recess formed in said main handleadjacent the transverse axis about which said jaw assembly pivots and atransversely extending projection carried by said jaw assembly adjacentthe free end thereof arranged for interlocking frictional engagementwith said locking recess when said jaws are moved into closed position;and a secondary handle connected to said jaw assembly and movabletherewith to a locking position adjacent said main handle for firstclosing and then locking said jaws.

2. The structure defined in claim 1 wherein the pivotally connected endof said jaw assembly is provided with a hole therein, a protuberanceformed on said handle adjacent the forward end thereof, normallyprojecting into said hole, and a compression spring disposed in saidhole acting in opposite directions against said protuberance and saidjaw assembly.

3. A gripping device comprising: a main handle having a forward endportion; a jaw assembly including pivotally interconnected first,second, and third jaws, each having cooperating curved surfaces forembracing a substantially cylindrical object when said jaws are pivotedtoward one another into closed position; said first jaw being pivoted ona transverse axis to the forward end portion of said main handle; saidsecond jaw being respectively pivoted at each end thereof to said firstand third jaws; said third jaw including a free end; a secondary handleconnected to said third jaw at the end thereof opposite said free endfor moving said jaws into closed position; biasing means acting betweensaid first jaw and the forward end portion of said main handle forcontinuously urging said jaws toward said main handle; and cooperablemeans including a transverse locking recess formed in said main handleadjacent the transverse axis about which said first jaw pivots and atransversely extending projection carried by said third jaw adjacent thefree end thereof arranged for interlocking frictional engagement withsaid locking recess for retaining said jaws in closed position.

4. The structure defined in claim 3 wherein the continuously biasingmeans includes: an arcnate fingerlike protuberance on the forward endportion of said main handle adjacent said first jaw, said first jawbeing formed with a laterally protruding portion adjacent said handleand having a hole therein, the outer end of said protuberance beingdisposed in said hole, and a compression spring in said hole acting inopposite directions against said first jaw and said protuberance.

References Cited in the file of this patent UNITED STATES PATENTS1,243,543 Moran Oct. 16, 1917 1,764,124 Smith June 17, 1930 2,329,196Hambly Sept. 14, 1943 FOREIGN PATENTS 214,541 Great Britain Apr. 24,1924

